Forest director Simon Clark said: “We don’t advocate people smoking in children’s play areas but there’s no justification for a taxpayer-funded campaign to ban it.

“Very few adults smoke in playgrounds and there’s no evidence that smoking in the open air is a health risk to third parties, including children.

“The argument that it encourages children to start smoking is also very weak. Teenagers smoke because of peer pressure or the influence of family members. The sight of a stranger smoking has never been a significant factor.

“This is prohibition by stealth. Councils are using playgrounds as a Trojan horse to prohibit smoking in other outdoor areas such as beaches, parks and squares.”

Mr Clark said the campaign was ‘ an abuse of public money’ because ‘very few people believe that tackling smoking is a high priority for local government’.

He also said it was wrong to discourage the use of e-cigarettes because they are used by people trying to quite smoking.

A council spokesman said the campaign was aimed at changing social norms around Sheffield.

“Research shows children are less likely to start smoking if they do not view the activity as a normal part of everyday life,” they said. “As smoking becomes less visible it should reduce smoking uptake by young or new smokers.”

The council consulted more than 1,500 people, including smokers and non-smokers, and said four in five respondents backed a smoke free playground voluntary code in Sheffield.

The spokesman said: “The decision to include electronic cigarettes in the smoke free children’s play parks policy was taken following the consultation process with park users. We fully support and continue to invest in helping our communities to quit smoking and stopping our children from taking up smoking.”

They added: “However, we believe we have to be consistent in policies to protect children. It is illegal to sell electronic cigarettes or e-liquids to someone under 18.

“It is also illegal to buy e-cigarettes for someone aged under 18. Therefore we believe that it is not unreasonable to ask people to refrain from vaping in areas designed for young children.”